Cationic thermosetting resin composition for improving wet strength of paper

ABSTRACT

WHERE R is alkylene or arylene with (b) an amino carbonyl compound, (c) a diamine or polyalkylene polyamine, and (d) itaconic acid, and (2) one or both of two secondary polyamine polyamide polymers B and C, the former being prepared by reacting reactants (b) and (c), above, and (e) epichlorohydrin, and the latter secondary polymer C being prepared by reacting reactants (a), (b), (c) and (e), above. The mixture of polymers is rendered thermosetting by further reaction with additional epichlorohydrin. A considerable number of resins for imparting wet strength to paper have been developed in recent years. Most of these resins are of the thermosetting type, thermosetting properties generally having been provided by means of crosslinking agents such as halohydrins.   Cationic thermosetting resin compositions useful in imparting wet and dry strength to paper are formed of a mixture of (1) a primary water-soluble polyamine polyamide polymer A, prepared by reacting (a) a heterocyclic dicarboxylic acid of the formula:

limited States atent 1 Munjat et a1.

[ Mar. 4, 1975 CATIONHC THERMOSETTING RESIN COMPOSITION FOR IMPROVING WET STRENGTH OF PAPER [75] inventors: Francis S. Munjat, Philadelphia;

Samuel Ho Kim, l-laverford, both of Pa.

[73] Assigneez E. F. Houghton and Company,

Philadelphia, Pa.

22 Filed: June 7,1973

21 Appl. No; 367,801

[52] US. Cl 162/164, 260/857 TW [51] Int. Cl D2lh 3/58, C08g 41/04 [58] Field of Search..... 162/164, 168; 260/857 TW,

260/857 R, 785 C, 785 A, 785 L, 785 TE [56] References Cited UNITED STATES PATENTS 3,250,664 5/1966 Conte et al. 162/164 3,320,215 5/1967 Conte et a1. 162/168 3,395,130 7/1968 McDowell et a1 260/785 C 3,761,350 9/1973 Munjat et a1. 162/164 ,Primary E.\'aminerS. Leon Bashore Assistant E.\' aminer-Wi11iam F. Smith Attorney, Agent, or Firnz--Howson and Howson [57] ABSTRACT Cationic thermosetting resin compositions useful in imparting wet and dry strength to paper are formed of a mixture of (1) a primary water-soluble polyamine polyamide polymer A, prepared by reacting (a) a heterocyclic dicarboxylic acid of the'formula:

0 i CH HOOC-R-N I 0 CH CH COOH where R is alkylene or arylene with (b) an amino carbonyl compound, (0) a diamine or polyalkylene polyamine, and (d) itaconic acid, and (2) one or both of 'two secondary polyamine polyamide polymers B and provided by means of crosslinl-zing agents such as halohydrins.

10 Claims, N0 Drawings 1 CATIONIC THERMOSETTING RESIN COMPOSITION FOR IMPROVING WlET STRENGTH OF PAPER 'tion Ser. No. 367,802 with certain other cationic thermosetting resins which, although they do not provide paper with the same degree of wet strength as those of said application; nevertheless, are less expensive to prepare, and thereby obtain compositions which when applied to paper provide the paper with wet strengths similar to, and in some cases better than, those obtainable by use of the more expensive resins of application Ser. No. 367,802.

It is, therefore, an object of the present invention to provide novel cationic thermosetting resin composio II CH aooc-R-i/ (I) ca ca coon where R is an alkylene radical containing from 1 to carbon atoms or an arylene radical, and for each mol of dicarboxylic acid,

b. from 0 to 4 mols of an amino carbonyl compound which is an amino acid of the formula:

. or a lactam of the formula:

tions for providing paper with adequate wet strength yet are less expensive to prepare than many resins which provide similar wet strengths.

Another object of this invention is to provide resin compositions which undergo accelerated natural aging when incorporated in paper, thereby giving a more rapid increase in dry strength and wet strength.

A further object of the invention is the provision of cationic thermosetting resin compositions which reduce foaming on, the paper machine.

A still further object of the invention is to provide resin compositions which increase softness in tissues while at the same time improve both wet and dry strength.

These and other objects of this invention will become apparent from a consideration of this specification and appended claims.

The cationic thermosetting resin compositions of this invention comprise a mixture of a primary polyamine polyamide polymer A, and a secondary polyamine polyamide polymer B or C or combination of such secondary polymers, said mixtures of polymers rendered thermosetting by epichlorohydrin. Primary polymer A may be preparedby reacting:

a. a heterocyclic dicarboxylic acid of the formula:

ll ll -C-CH-CH where R is an alkylene radical containing from 1 to 10 carbon atoms or an atom;

c. from 1 to 3 'mols of an amine which is a diamin'e of the formula:

H N- is an alkylene radical containging from 3 m 10 carbon atoms;

0. from 1 to 3 mols of an amine which is a diaminc of the formula:

or a polyalkylene polyamine of the formula:

H N-(R'NH),,-H

where R and R are alkylene groups containing from 2 to 6 carbon atoms, and n is an integer from 1 to 5; andd. from 1 to 2 mols of itaconic acid to form a water soluble polyamine polyamide polymer of the following repeating structure:

z is to 4', and R,-R, R,R, R" and n are as defined to allow the addition to the double bond to take place followed by cyclization as described in detail in copending application Ser. No. 367,802. Cylization can be observed by two mols of water of condensation being rapidly generated below 150C., signifying a course other than amide formation in which water is generated only at temperatures above 150C.

The unsymmetrical heterocyclicdicarboxylic acid reactant (a) may be prepared by reacting itaconic acid with an amino acid of formula (II) or a lactam of formula (III) in substantially equimolar proportions as described in co-pending application Ser. No. 367,802. The reaction may be carried out in aqueous solution; however, the amount of water used should be adjusted to provide suitable reaction conditions to produce the product desired. Thus, although the aqueous solution of reactant may contain up to about 50 by weight of water, subsequent concentration by distillation may reduce the reaction solution to 5 to of Water. The reactants are merely mixed with water in the stated proportions, solubilized by heating to 105 to about 130C.

for a period of from about 2 to 5 hours. In the case of the amino acids, concentration of the reacting solution can begin immediately after solubilization; with lactams, sufficient time must begiven to accomplish hydrolysis to amino acid. Initially, there is formed an intermediate tricarboxylic acid by addition of the itaconic acid methylene double bond to the amino group of the amino acid. The solution then only needs to be concentrated to form the heterocyclic dicarboxylic acid.

The reaction mechanism involved in forming one of the preferred heterocyclic dicarboxylic acids, namely, 1-(p-carboxyphenyl)-4-carboxypyrrolidone, may be illustrated by the following equations wherein itaconic acid and p-amino-benzoic acid are the reactants. The dicarboxylic acid separates from the reaction media and is isolated as a crystalline material.

H0oc -NH, Hoocuolnooon H2O (VII) or a different amino carbonyl compound may be used in forming the polymer'as was employed in forming the heterocyclic acid.

As noted, the amino acids which may be used have the formula:

where R is an alkylene radical containing from 1 to 10 carbon atoms or an arylene radical. The alkylene radical may be a straight or branched chain aliphatic group. Preferably, where R is an alkylene radical, the amino acids are alpha-substituted amino acids such as alanine, leucine, valine, and alpha-amino butyric acid. Other suitable amino acids include glycine, beta-alanine, 4- amino butyric acid, 6-amino-caproic acid, and l lamino undecanoic acid.

Aromatic amino acids which have been found useful in preparing the novel cationic thermosctting resins of the invention may contain such radicals as phcnylene. naphthylene, etc., and alkyl substituted forms thereof. The amino group may be directly substituted on the aromatic nucleus, or it may be on a terminal carbon atom of an alkyl group of l to 7 carbon atoms substituted on the aromatic ring. Similarly, the carboxylic acid group may be directly substituted on the aromatic ring or on a terminal carbon atom of an alkyl group containing from 1 to 7 carbon atoms substituted on the aromatic ring. Water solubility of the final resin characterizes the useful amino and carboxyl group containing compounds. Typical of useful aromatic amino carboxylic acids are 0, m, and p-amino benzoic acid, p-(Z-aminoethyl) benzoic acid and p-aminophenylacetic acid.

Lactams which are suitable for use in preparing the resins of this invention have the formula:

Rll

(III) formula (IV) or certain polyalkylene polyamines of formula (V).

In the diamines, the primary amine groups are separated by an' alkylene radical containing from 2 to o carhon atoms. Thus, suitable diamines include ethylene. propylene, butylenc, pentylene. and hexylene diainiue. Ethylene and propylene diamine are particularly preferred diamines inasmuch as they are somewhat more economical than the higher diamines.

A variety of polyalkylene polyamines including polyethylene polyamines, polypropylene polyamines, polyhutylcnc polyamines, and the like can be employed to produce the polyamide, of which the polyethylene polyamines represent an economically preferred class. More specifically, the polyalkylene polyamines employed are polyamines containing two primary amine groups, and at least one secondary amine group in which the nitrogen atoms are linked together by alkylene groups containing from 2 to 6,carbon atoms. The nitrogen atoms may be attached to adjacent carbon atoms in the ethylene groups or to. carbon atoms further apart, but not to the same carbon atom. Polyamines such as diethylenetriamine, triethylenetetramine, tetraethylenepentamine, dipropylenetriamine, and the like, which can be obtained in reasonably pure form can be used as well as mixtures thereof-and mixtures of various brude polyamine materials. For exll 0 0 ll CRN HOC CPI-CI-I -I-INUK'"N10 ample, the mixture of polyethylene polyamines obtained by the reaction of ammonia and ethylenedichlorides, refined only to the extent of removal of chlorides, water, and excess ammonia, can be employed in the re action with the dicarboxylic acid.

More preferred are the polyethylene polyamines containing from two to four ethylene groups, two primary amine groups, and from one to three secondary amine groups.

The term polyalkylene polyamine, employed in CH?- CI-Ill (NHR C D- (HNR' )NHCH 0 l o C-CH,2

(R NHl lRN In formula (VIII) R,R"', n and z are as set forth above.

The intermediate reaction product with water added is cooled, and an excess of itaconic acid is added with respect to carboxyl group to amine to obtain a further intermediate of the formula:

- CH- COH (IX) 0 and the whole is refluxed at a temperature of from about C. to C, preferably 120 to 136C, for

- 60 to 90 minutes to form the additional pyrrolidone groups in the chain. In the case of larger polyalkylene polyamines (V) where n equals 3 or more, the reaction product is added to the itaconic acid, and conversion to the pyrrolidone acid ceases when the amine content is equivalent to the carboxylic acid content, and is only about 50 when n is equal to 4. This further intermediate has the formula:

O 0 ll ll CH C O C"-CH2 O l l 0 NH)nCRN if C CH2 HOC-CH-C'H CH -CHC (NHRC)-(NHR"') N r O (X) 2 2 z n CHZ-CHCOH this specification and the claims, therefore, refers to and includes any of the polyalkylene polyamines referred to above and to mixtures thereof.

Rather than using solely a diamine or a polyalkylene polyamine, mixtures of the two types of amines, e.g., a mixture of ethylenediarnine and diethylenetriamine This intermediate product is further reacted with diamine (IV) or polyalkylene polyamine (V) to give a 65 water soluble polyamine polyamide polymer. Condensation is effected by raising the temperature to C. Those mols of water associated with the formation of the pyrrolidone ring are removed from the reaction site 7. below 150C. Water associated with vpolyamide fo'rma tion is removed above this temperature. The final primary polymer A has the formula:

. 8 or a polyalkyle'ne polyamine of the formula:

This polymer is diluted to 50% solids content with water.

A preferred polyamine polyamide polymer A is obtained by reacting lcarboxypentyl- 4-carboxypyrrolidone, caprolactam, diethylene tr iamine, and itaconic acid.

The proportions of the reactants described above in providing the-improved resins is quite important. It was found that the mol ratios of reactants: (a) heterocyclicdicarboxylic acid, (b) amino carbonyl compound, diamine or polyalkylene polyamine, and (d) itaconic acid employed in providing the water soluble polyamine polyamide polymer should be:

(b) to (a) & from about 0:1 to about 4:1.

-(c) to (a) from about 1:1 to about 3:1-

(d) to (a) fromvab'out l:l to about 2:1

Preferred mol ratios of the four reactants in obtaining resins of optimum wet strength (uncured and after cure) are (b) to (a) about 1:1, (c) to (a) about 3:1 and (d) to (a) about 2:1.

Polyamine polyamide polymer 8 may be prepared'by reacting: 1

b. from 1 to mols of an amino carbonyl compound which is an amino acid of the formula:

or a lactam of the formula:

1 (III).

where R' and R" are alkylene groups containing from- '--[HN(R "NH) cagbica where x can bel to 3 and y can be I to 5. A preferred process, by which-the water soluble poly.-

hydroXy polyamide polyamine'polymer B may be pre-- pared from the above-defined reactants, comprises mixing together in a suitable reactor the amino carbonyl compound (ll) or (III) and the amine (IV) or (V) and one mol of water, and heating the mixture for 2 to 3 hours at reflux (l05-C-.). This gives an intermediate of formula:

The reaction intermediate is cooled, and epichlorohydrin, reactant (e), is added incrementally controlling the temperature rise. of. formula:

After the addition of the epichlorohydrii'i, the reaction product is heated to a temperature from about to C, to.complete the reaction cycle, and give a polymer of formula:

- (m1(a ait) cii 'cucn This forms a further intermediate 9 Vacuum is applied for at least one half hour at the end of the reaction. This polymer B is diluted with water to give from about 35% to 50% solids content.

In this reaction secondary amines are produced from primary amine groups by means of epichlorohydrin which extends the polymer chain providing an economical method of obtaining multiple reaction sites for additional epichlorohydrin cross-linking agent in a polymer unit.

In making polymer B, the amino carbonyl, reactant (b) and the amine, reactant (c), are the same reactants as used in preparation of polymer A, above.

Polymer C is described and claimed in co-pending application Ser. No. 156,127 filed June 23, 1971, now U.S. Pat. No. 3,761,350. This polymer is prepared-by reacting:

a. a heterocyclic dicarboxylic acid, reactant (a) for polymer A, and for each mol of acid,

I /c-ca C(CH2)5N\ F) In 0 H OH H (XVII) ca -CH CNHCIIZCHZNCHZ CHZNHC (c11 ca caca Nca CHZNH- CHZCHZNIL 'HCl ti o c--ca 2 i xca N/ on VIII) g x 2 5V H NH ca CNHCH ca 30H ca iicu'caca iic ca N H NH 2 25 22 22 z zz z b. from 0-5 mols of amino carbonyl compound, reactant (b) for polymer A, and

c. from 1-4 mols of diamine or polyalkylene polyamine, reactant (c) for polymer A, and

e. from 1 to 3 mols of epichlorohydrin, to form a water soluble polyamine polyamide polymer.

As disclosed in co-pending application Ser. No. 156,127, now US. Pat. No. 3,761,350, a preferred process by which the water soluble polyamine polyamide polymer C may be prepared from the above-defined reactants comprises first mixing together in a suitable re- A mol of water is added to this mixture, and the whole is cooled to a temperature of from about to C., and epichlorohydrin is then added slowly. After addition of all the epichorohydrin, the mixture is again heated to a temperature from about 165C. to 215C. the water of condensation being removed during heating. The epichlorohydrin reacts with available primary amine groups and, in so doing, links together the prepolymers to form the water-soluble polyamine polyamide polymer. In addition, the reaction between the epichlorohydrin and the primary amine groups produces secondary amine groups which are available for crosslinking by means of epichlorohydrin.

A storage-stable solution'of the polyamine polyamide polymer C can be obtained by adding sufficient water to the polymer to provide a solution containing from about 35 to 75% solids.

The polymer contains the following repeating units:

40 resins of optimum wet strength (uncured and after cure) are for each mol of (a), one mol (b), two mols '(c), to one mol (e).

' In summary, the molar ratios of reactants for polymers A, IiandC as follows:

For polymer A, the mol ratio of reactants is: (b) to (a) 0:1 to 4:1

(c) to (a) 1:1 to 3:1

ttqltgtal; =1,... 9. 29.1... r

.actor the heterocyclic dicarboxylic acid, the amino car-' 50 th f r d ratio being:

bonyl compound, if any, and'the amine and heating the mixture at a temperature of from about C. to about C. under reflux conditions for a period of from about 30 to 60 minutes. During such heating, the components react to form low molecular weight prepoly- 55 mers. A low molecular weight unit obtained when using lcarboxypentyl-4-carboxy pyrrolidone, ca'prolactam, and diethylenetriamine as the reactants is as follows:

(b) to (a) 1:1 (c) to (a) 3:1 (d) to (a) 2:1

For polymer B, the mol ratio of reactants is: (c) to (b) 1:5 to 4:1 i

(e) to (b) 1:5 to 3:1

(e) to (c) 1:4 to 3:1

I I H y lo c-----ca N N o H Nca cH CH2CH2NHC(CH2)5 V H g (XVI) CH2CH CNH(CH2) 5CNH on on ca cH Na 11 1 the preferred ratios being:

'(c) to (b) 1:1

(e) to (b) 1:1

(e) to (c) 1:1

For polymer C, the mol ratio of reactants is:

(b) to (a) 0.1 to 5:1

(c) to (a) 2:1 to 4:1

(e) to (a) 1:1 to 3:] the preferred ratios being:

(b).to (a) 1:1

() to (a) 2:1

(e) to (a) 1:]

In the preparation of the finished resin composition of this invention, mixtures ofA and B, A and c, or A, B and C may be utilized. In the case of mixtures of polymers A and B, their mol ratios may be:

B to A l:l9 to 19:1 the preferred ratio being:

B to A 4 1:1.7

Similarly, mixtures of polymers A and C may be utilized, and their mol ratios may be:

C to A 1:19 to 19:1 the preferred ratio being:

C to A 1:1

In thecase of mixtures of polymers A, B and C, the combined amounts of polymers B and C should be the same as the amount of polymer B or C in the binary mixtures of A and B or A and C.

The mixtures of polymers at about 20% to 30% solids is treated with epichlorohydrin at 40C. to 60C., and the reaction is continued at about 70C. to 76C., until the pH of the system reaches about 6.9 to 7.2, or the Gardner Holdt viscosity is greater than J, whichever course is desired to follow. The system is then diluted with water to the desired solids content and acidified to pH 5 with acid. Generally, from about 0.5 to about 1.8 mols of epichlorohydrin per secondary amine group should be used in rendering the polymers thermosetting. The preferred amount of epichlorohydrin used for such purpose is about one mol for each secondary amine group on the polymers from the mixture.

The cationic thermosetting resins of this invention impart improved wet and dry strength to paper (uncured or cured) at reduced cost whether made under acid, alkaline, or neutral conditions and accelerated natural aging.

The resin preferably is incorporated into paper pulp atany point on the wet end of the paper machine, e.g., at the beater, stock chest, head box, etc. The resin may also be applied to a web of paper as by immersing the web in a solution of the resin, by spraying, etc., followed by heating to cure the resin. For most purposes, adequate wet strength is developed by simply drying the sheet and allowing natural aging to take place.

Adequate wet strength may be obtained by incorporating in the paper from about 0.15% to about 3% of the resin based on the dry weight of the pulp. Higher percentage additions may be made for special purposes.

Paper and pulp slurries having a pH of from 4.5 to l 1 in the first step determines the quantity of reactant (a) that is formed. The excess reactant remains in the system and is available for further reaction.

EXAMPLE NO. 1

v Polymer A Into a one liter flask equipped with condenser, thermometer, and stirrer were charged 68.5 g. (0.5 mols) of p-aminobenzoic acid, 65 g. (0.5 mols) of itaconic acid, and 54 ml. of water. The mixture was refluxed for two hours. To this reaction intermediate were added 103 g. (1 mol) of diethylenetriamine. The whole was then refluxed at 132C. for 1 hour. The reaction mixture was again cooled'to 26C. and 132 g. (1.01 mols) of itaconic acid were added, and the mixture heated to reflux for 1 hour at 125C. At 117C. were added 51.5 g. (0.5 mols) of diethylenetriamine. The whole was then heated to l80-190C. with vacuum applied for A of an hour at this temperature. The finished polymer A was diluted to 50% solids content with water, and the Gardner-Holdt viscosity was G at 25C.

The polyamine polyamide polymer A comprised one mol of p-aminobenzoic acid, three mols of itaconic acid, and three mols of amine. The amine equivalent based on secondary amine is 236.7.

.Polymer B Into a one liter flaskequipped with a condenser, thermometer, and stirrer were charged 60 g. (1 mol) of ethylenediamine, 113 g. (1 mol) of caprolactam, and 13.3 ml. of water. This mixture was refluxed for 3 hours at 124C. and then cooled to 29C., adding 18 ml. of wamay be effectively treated with resins of this invention.

The invention is further illustrated by the following examples. In each of examples 1 to 11, inclusive, the heterocyclic dicarboxylic acid reactant (a) is formed in situ by reaction of reactants (b) and (d) in the initial steps. Since reactants (b) and (d) react in equimolar proportion to form reactant (a), the limiting reactant ter. Immediately, 92.5 g. (1 mol) of epichlorohydrin.

were added incrementally, controlling the exotherm with cooling so as not to exceed C. After all the epichlorohydrin was added, the whole was heated to 204C., collecting 31.5 ml. of distillate. The reaction mixture was diluted to 50% solids with. 233.8 ml of water plus the collected distillate. The Gardner-Holdt viscosity of the resulting polymer B (polyhydroxy polyamine polyamide) was I+ at 25C.

Polymer B comprised one mol of amine, one mol of amino acid, and one mol of epichlorohydrin. Amine equivalent based on secondary amine 132.8 (includes secondary amine hydrochloride).

Conversion to Cationic Thermosetting Resin In a one liter flask were charged 74.34 g. (0.14 mols) .of the above polymer B, 99.40 g. (0.7 mols) of the polymer A, and 148 ml. of water. This mixture was heated to 50C. Then, 22.67 g. (0.245 mols) of epichlorohydrin were added dropwise over a period of 6 minutes, allowing the exotherm to 57C. The mixture was held at 75C. until the Gardner-Holdt viscosity was greater than J. The resin mixture was then diluted with 203.3 ml. of water to 20% solids and-acidified to pH 5 (Accutint paper) with sulfuric acid. The Gardner-Holdt viscosity of the 20% solution was E at 25C. The mol ratio of polymer B to polymer A was 1:05, and ratio of epichlorohydrin to amine equivalent 0.5:1'.

EXAMPLE NO. 2

Polymer A Into one liter flask were charged 226 g. (2.0 mols) of caprolactam, g. (one mol) of itaconic acid, and 36 ml. of water. This mixture was reluxed for 2 hours. To this reaction intermediate were added 203 g. 1.97 mols) of diethylenetriamine. which was then refluxed at 143C. for 1 hour. The reaction mixture was again cooled to 65C., and 260 g. (2 mols) of itaconic acid were added at 82C. Then, the mixture was heated to reflux for one hour at 131C. At 115C. were added 103 g. 1 mol) of diethylenetriamine. The whole was then heated to 177C. with vacuum applied until the finished polymer A at 50% solids reached the Gardner- Holdt viscosity of U at 25C. 1

The polypyrrolidone polyamine polyamide polymer A comprised two mols of caprolactam, three mols of itaconic acid, and three mols of diethylenetriamine. The amine equivalent based on secondary amine was 272.3. Polymer B A polyhydroxy polyamine polyamide polymer B was prepared from 51.5 g. (0.5 mols) of diethylenetriamine, 68.5 g. (0.5 mols) of p-aminobenzoic acid, 36

ml. of water and 46.2 g. (0.5 mols) of epichlorohydrin. The procedure of Example'No. 1 for preparation of polymer B was essentially followed. The resulting polymer B solution contained,50% solids and had a viscosity of A on the Gardner-Holdt scale at 25C.

This polyhydroxy polyamine polyamide polymer B comprised one mol of amine, one mol of aromatic amino acid, and one mol of epichlorohydrin. The amine equivalent based on secondary amine 104.8 (includes secondary amine hydrochloride). Conversion to Cationic Thermosetting Resin Into a one liter flask were charged 18.87 g. (0.03 mols) of the above polymer B, 84.8 g. (0.052 mols) of the polymer A, and 103.3 g. of water. This mixture was heated to 53C. at which temperature 22.73 g. (0.246 mols) of epichlorohydrin were added dropwise, allowing the reaction temperature to rise up to 56C. The mixture was then held at 75C. until the Gardner-Holdt viscosity was greater. than J. The resulting thermosetting resin solution was immediately diluted with 215.2 ml. of water to 15% solids and acidified with sulfuric acid to Accutint pH 5.4. The Gardner-Holdt viscosity of the 15% solution was C at 25C. The mol ratio of the polymer B to the polymer A was 1:1.73, and the ratio of epichlorohydrin to amine equivalent 1;].

EXAMPLE NO. 3

Polymer B g A polyhydroxy polyamine polyamide polymer B was prepared from 155 g. (1.5 mols) diethylenetriamine, 170 g. (1.5 mols) of caprolactam, 27 ml. of water and 146 g. 1.58 mols) of epichlorohydrin according to the procedure of Example No. 1. The resulting polymer B contained 70% solids with the Gardner-Holdt viscosity of Z4 at 25C.

This polymer B comprised one mol of diethylenetriamine, one mol of caprolactam, and one mol of epichlorohydrin. The amine equivalent based on secondary amine 102.8 (includes secondary amine hydrochloride). Conversion to Cationic Thermosetting Resin Into oneliter flask were charged 11.5 g. (0.027 mols) of the above polymer B, 72.2 g. (0.044 mols) of the polymer A prepared in Example No. 2, and 109.3 ml. of water. The mixture was heated to 51C. before addingdropwise 29.22 g. (0.315 mols) of epichlorohydrin over a period of 5 minutes. The resulting resin solution was keptat 75C. until the pH of the product reached 7.2 on an Accutint ph paper. The resin solution was immediately diluted with 275.8 ml. of water to solids.

Formic acid was used in acidifying thesolution to Ac:

cutint pH 5.4. The Gardner-Holdt viscosity of the 15% solution was B at 25C. The mol ratio of the polymer B to the polymer A was 1:1.7, and the ratio of epichlorohydrin to amine equivalent 1.5:1.

EXAMPLE NO. 4

Polymer A A polypyrrolidone polyamine polyamide polymer A- was prepared from 226 g. (2 mols) of caprolactam, 390 g. (3 mols) of itaconic acid, and 293.55 g. (2.85 mols) of diethylenetriamine, using the procedure of Example No. 2, except there was no pre-cooling of reaction intermediates at each successive chemical addition step. The polymer A at 65% solids had a Gardner-Holdt viscosity of 261- at 27C.

The polypyrrolidone polyamine polyamide polymer A comprises two mols of caprolactam, 3 mols of itaconic acid, and 2.85 mols of diethylenetriamine. The amine equivalent based on secondary amine is 281.3. Polymer B Into a one liter flask were charged 113 g. (1 mol) of caprolactam, 18 ml. of water, and 103 g. (1 mol) of diethylenetriamine. The mixture was refluxed for 2 hours and then heated further to distill off the water added to 163C. Upon cooling to about 80C., the collected distillates were returned to the flask.

To a second one liter flask were transferred 7.02 (0.03 mols) of the above intermediate, and added 54 ml. of water and 2.78 g. (0.03 mols) epichlorohydrin at 34C. The resulting polyhydroxy polyamine polyamide polymer B comprised one mol of amine, one mol of amino acid, and one mol of epichlorohydrin. The

amine equivalent based on secondary amine 102.8

(includes secondary amine hydrochloride).

Conversion to Cationic Thermosetting Resin Into the above second flask containing the finished polymer B (0.03 mols) were charged 64 g. (0.052

mols) of the polymer A, and 82.2 ml. of water. This mixture was heated to 52C. Then, 32.9 g. (0.356 mols) of epichlorohydrin were added slowly while the reaction mixture was maintained at 5261C. Reaction continued at C. until the reaction product reached the Gardner-Holdt viscosity greater than J. Immediately, 313.1 ml. of water were added to obtain a 15% solids solution and the solution acidified with sulfuric acid to Accutint pH 5.3. The Gar'dner-Holdt viscosity of the 15% solution was less than A at 25C. The mol ratio of the polymer B to the polymer A was 1:1.73, and the ratio of epichlorohydrin to amine equivalent 1.5: 1.

EXAMPLE NO. 5

EXAMPLE NO. 6

Into a one liter flask were charged 98.04 g. (0.06

mols) of the polymer A of Example No. 2 and 107 ml.

held at 76C. until the solution reached the Gardner-' EXAMPLE NO. 7

Polymer A A polypyrrolidone polyamine polyamide polymer A was prepared from 237.3 g. (2.1 mols) of caprolactam, 136.5 g. (1.05 mols) of itaconic acid, 72.1 g. (.7 mols) of diethylenetriamine, and 66.1 g. (0.35 mols) of tetraethylenepentamine according to the procedure of Ex- I ample 2. This polymer A at 50% solids had a Gardner- Holdt viscosity of Z2 at 25C.

The polymer A comprised six mols of caprolactam, 3 mols of itaconic acid, 2 mols of diethylenetriamine, and 1 mol of tetraethylenepentamine. The amine equivalent based on secondary amine is 225.8. Polymer c Into a one liter flask equipped with condenser, thermometer, and stirrer were charged 130 g. (1 mol) of itaconic acid, 300 g. of water, and 137 g. (1 mol) of paminobenzoic acid. The reaction mixture was heated to reflux and concentrated to one third the volume of water, and the solid heterocyclic dicarboxylic acid began to precipitate from solution. This acid has a melting point of 279288C. and an acid number of 435 (theory 452).

The above mixture was cooled and 206 g. (2 mols) of diethylenetriamine and 113 g. (1 mol) of caprolactam were added. The temperature was held below 105C. during the addition. After solution of the materials, the reaction mixture was further cooled to 40C. and 92.5 g. (1 mol) of epichlorohydrin were added incrementally controlling the exotherm to 110C. with cooling. After the epichlorohydrin was added, the mixture was heated to 190 -195c. for one-half hour. The

polymer C was diluted to 50% polymer solids with 570 g. of water. The Gardner-Holdt viscosity of this solution was E'at 25C.

The polypyrrolidone polyhydroxy polyamine polyamide polymer C comprised 1 mol of heterocyclic dicarboxylic acid, 1 mol of amino acid, 2 mols of amine, and 1 mol of epichlorohydrin. Amine equivalent based on secondary amine 156.2 (includes secondary amine hydrochloride). Conversion to Cationic Thermosetting Resin:

A solids resin solution was prepared from 34.98 g. (0.028 mol) of the above polymer c, 63.2 g. (0.028 mol) of the polymer A, 25.65 g. (0.277 mol) of epichlorohydrin, and 374.45 ml. of water, following essentially the procedure used for Example 3, except phosphoric acid was used for the final acidification. The Gardner-Holdt viscosity of the 15% solution was A+ at 25C. The mol ratio of the polymer C to the polymer A was 1:1, and the ratio of epichlorohydrin to amine equivalent 1.1:1.

EXAMPLE NO. 8

Polymer C A polypyrrolidone polyhydroxy polyamine polyamide polymerC was prepared from 91 g. (0.7 mols)of 6-aminohexanoic acid, 12.5 g. of water, 90.5 g. (0.7 mols) of itaconic acid, 143 g. (139 mols) ofdiethylenetriamine, and 64.3 g. 0.7 mols) of epichlorohydrin according to the procedure of Example No. 7. This polymer C at 50% solids had a Gardner-Holdt viscosity of Q+ at 25C.

The polymer C comprised one mol of itaconic acid,

one mol of 6-aminohexanoic acid, one mol of epichlorohydrin, and two mols of diethylenetriamine. The amine equivalent based on secondary amine 135.4 (includes secondary amine hydrochloride). Conversion to Cationic Ther'mosetting Resin:

Into a 1 liter flask were charged 29.24 g. (0.027 mols)'of the above polymer C, 83.3 g. (0.0675 mols) of the polymer A of Example No. 4, and 196.3 ml. of water. The mixture was heated to 50C. before adding dropwise 55.54 g. (0.6 mols) of epichlorohydrin over a period of six minutes. Reaction was first held at C. for 2 hours and then continued to 86C. until the Gardner-Ho'ldt viscosity was greater than H. Immediately 142.7 ml. of water were added to obtain a 2 5% solids solutionwhich were acidified to AccutintpH 4.8 with sulfuric acid. The Gardner-Holdt viscosity of the 25% solution was C at 25C. The mol ratio of the polymer C to the polymer A was 112.5, and the ratio of epichlorohydrin to amine equivalent 2:1.

EXAMPLE NO. 9

Polymer C A polypyrrolidone polyhydroxy polyamine polyamide polymer C was prepared from g. (1.46 mols) of itaconic acid, 330 g. (2.92 mols) of caprolactam, 30 g. of water, 300 g. (2.91 mols) of-diethylenetriamine, and 135 g. (1.46 mols) of epichlorohydrin, essentially following the procedure of Example No. 7. This polymer C at 50% solids has a Gardner-Holdt viscosity of U at 25C.

The polymer C comprised 1 mol of itaconic acid, 2 mols of amino acid, 2 mols of amine, and 1 mol of epichlorohydrin. The amine equivalent based on secondary amine 154.6 (includes secondary amine hydrochloride).

Conversion to Cationic Thermosetting Resin:

Following the procedure of Example No. 3, a 15% solids resin solution was prepared from 47 g. (0.038 mols of the above polymer C, 60.08 g. (0.0367 mols) of the polymer A made according to Example No. 2. The Gardner-Holdt viscosity of the 15% solution was D+ at 25C. The mol ratio of the polymer C to the polymer A was 1.03:1, and the ratio of epichlorohydrin to amine equivalent 0.8: 1.

EXAMPLE NO. 10

Polymer A A polypyrrolidone polyamine polyamide polymer A was prepared from g. (1.5 mols) of itaconic acid,

56.5 g. (0.5 mols) of caprolactam, 9 ml. of water 103 g. (1 mol) of diethylenetriamine, and 37 g. (0.5 mols) of 1,3-diaminopropane according to the procedure of Example No. 2. The polymer A at 50% solids had a Gardner-Holdt viscosity of G at 25C.

The polymer A comprised 3 mols of itaconic acid, 1 mol of amino acid, and 3 mols of amine. The amine equivalent based on secondary amine is 337.5. Polymer c.

A polypyrrolidone polyhydroxy polyamine polyamide polymerC was prepared from 113 g. 1 mol) of caprolactam, 120 g.(2 mols) of ethylenediamine, 130 g (1 mol) of itaconic acid, and 92.5 g. (1 mol) of epichlorohydrin using the procedure of Example No. 7. This polymer C at 50% solids had a viscosity of N on the (jardncr-Holdt scale at 25C. The polymer C comprised 1 mol of itaconic acid, 1 mol of caprolactam, 2 mols ofethylenediaminc, and 1 mol ofepichlorohydrin. The amine equivalent based on secondary amine 209.8 (includes secondary amine hydrochloride). Conversion of Cationic Thermosctting Resin:

A 25% solids solution was prepared from 20.4 g. (0.024 mols) of the above polymer C, 162 g. (0.12 mols) of the polymer A, 31.97 g. (0.346 mols) of epichlorohydrin. and 278 ml. of water, following the procedure of Example No. 8. The viscosity of the 25% solution was D+ at 25C. on the Gardner-Holdt scale.

The mo'l ratio of the polymer C to the polymer A was- 1:5 and the ratio of epichlorohydrin to amine equivalent 1.211. Preparation of Paper Samples A bleached sulfite was beaten in a Valley beater. The pulp was adjusted to a pH value of 6.8 and 0.75% by weight, based on weight of dry pulp, of the resins described in the. above examples, were applied to the stock. 43 lb. per ream (TAPPI Standard) sheets were made on the Noble and Wood handsheet machine without a closed white water system. The handsheets were dried 3 minutes at 105C., and portions of them were later cured for 1 hour at 105C.

TABLE 1 Wet Tensile Strength (oz/in.)

Example No. Off Machine Cured Blank (no resin) 16.1 22.9 1 Polymers A +8 48.8 91.6 2 do do. 73.9 118.4 3 do do. 87.1 149.1 4 do. do. 84.7 147.5 5 Polymer B 48.8 101.2 6 Polymer A 89.0 144.4 7 Polymers A +C 54.4 102.7 g 8 do. do. 86.7 136.7 9 do. do. 51.9 101.6 I 10 do. do. 60.7 109-.1

Set forth in Table 11 are the dry tensile strengths provided by the cationic thermosetting resins of the several Commercially preferred resin compositions of this invention are evaluated separately in TAble [11. Preparation of Paper Samples An 80% softwood and hardwood bleached sulfite was beaten in a Valley beater. The pulp was adjusted to a pH value of 7.0 and the resins described in Example Nos. 3, 4 and 8 were applied to the stock at the rate of 0.75%, based on the dry weight of pulp. 43 lb. per ream (TAPPI Standard) sheets were made on the Noble and Wood handsheet machine without a closed white water system. The handsheets were dried 3 minutes at C., and portions of them were later cured for 1 hour at 105C.

TABLE 1111 Example Wet Tensile (oz./in.) Dry Tensile (oz/in.)

No. Off Machine Cured Off Machine Cured Blank 12.9 21.8 381.6 401.1 3 A B 86.0 159.4 463.7 475.0 4 do. 86.0 161.6 487.9 489.7 8 A C 82.1 153.0 450.6 453.3

EXAMPLE NO. 11

This example shows further advantages of resin compositions of this invention when applied to paper in various amounts and over a range of pH values.

Polymer A Into a 2 liter flask equipped with condenser. thermometer, and stirrer were charged 36 g. water, 226 g. caprolactam, and g. of itaconic acid. This mixutre was heated at 105C. for 1 hour and then heated to reflux for 3 hours. The reaction intermediate was cooled, 206 g. of diethylenetriamine were added, and the resulting mixture was then refluxed for 1 hour. The reaction mixture was again cooled and 273 g. of itaconic acid were added, and the mixture held at 105C. for 1 hour and then heated to reflux. Cooling was again applied, and 108 g. diethylenetriamine were added. The reaction mixture was then heated to 188C. with vacuum applied for one-half hour at this temperature. The resin diluted to 50% solids content, and the Gardner- Holdt viscosity of the diluted solution was U at 25C. The amine equivalent of the polymer based on secondary amine is 272.3.

The polymer A comprised one mol hcterocyclic dicarboxylic acid, 1 mol amino carbonyl, 1.5 mols amine and about 2 mols of epichlorohydrin.

78 g. of the above product were diluted with 1 16 ml. of water and heated to 50C. g. of epichlorohydrin were added dropwise, and the reaction'was held at 70C. until the Gardner-Holdt viscosity was greater than I. The solution was then diluted with 343.5 ml. of water to 10% solids and acidified to pH 5 with sulfuric acid. The ratio of epichlorohydrin to secondary amine was 1.25 to 1. This 10% resin solution was used for comparative tests.

Polymer B A polyhydroxy polyamine polyamide polymer B was prepared from 113 g. of caprolactam, 18 g. of water, 103 g. of diethylenetriamine, and 101.75 g. olcpichlorohydrin in the following manner. Caprolactam, water, and diethylenetriamine were refluxed for 3 hours at 148C, cooled to 40C. when epichlorohydrin was added incrementally with cooling. After all the epichlorohydrin was added, the whole was heated to 185C., /2 hour being under vacuum. The reaction mixture was diluted to 50% solids with 308.5 g. of water. The Gardner-Holdt viscosity of the diluted solution was W. The secondary amine equivalent was 102.8.

The polymer B comprised 1 mol of caprolactam, 1 mol of amine, and one mol of epichlorohydrin.

52 g. of the above polymer B were charged to a 1 liter flask and diluted with 81 ml. of water. This solution was heated to 50C., and 24 g. of epichlorohydrin were added dropwise over a 15 minute period. The reaction was continued at 70C. until the pH of the solution reached 6.9. At this point, 343 ml. of water were added and the pH adjusted to 5.1 with sulfuric acid. The product contained 10% resin solids, and the ratio ofepichlorohydrin to secondary amine groups was 1.03 to 1.0. The 10% product was used for comparative tests. CatiOnicThermOSetting Resin (Polymers A B) .A polymer mixture was obtained by combining 30 g. of polymer B with 81.7 g. of polymer A. 76.8 g. of the above polymer solution were diluted with 149.2 ml. of water and heated to 51C. 23.5 g. of epichlorohydrin were added dropwise over 6 minutes. The reaction was continued at 72 to 75C. until a Gardner-Holdt viscosity greater than .1 was obtained. Dilution with 369.5 mls. of water gave a 10% solution which was acidified to pH with sulfuric acid. The Gardner-Holdt viscosity of the finished product was A-B at 25C. The ratio of epichlorohydrin to secondary amine was 1.27 to 1. Preparation of Paper Samples An 80% softwood and 20% hardwood belached sulfite was beaten to a Canadian Freeness Value .of 450 cc in a Valley beater. The pulp was adjusted to a pH value of 6.8 with sodium carbonate and variable amounts of the resins described as A, B, and A+B were applied to the stock (0 to 1%) based on the dry weight of pulp. 43 lb. per ream (TAPPI Standard) sheets were made on the Noble and Wood handsheet machine without a closed white water system. The handsheets were dried 3 minutes at 105C., and portions of them were later cured for 1 hour at 105C.

TABLE IV Wet Strength (oz./in.)

Table IV shows the increase in wet strength for the resin composition comprising a mixture of polymers A and B over either resin alone, at concentrations of resin equal to or less than 1%. The dry strengths show an improvement over the blank.

As stated above, polymer B is cheaper than polymer A, but provides poorer wet strength. Therefore, the

combination of A and B gives unexpectedly greater strength at a lower price.

TABLE V Effect of pH Example No. 1 l

Resin Composition Comprising a Mixture of Polymers A and B Wet Strength (oz./in.) Dry Strength (oz./in.)

Table V shows the good wet and dry strength of a resin composition of this invention (Polymers A B) over a broad range of pH, fulfilling one of the stated objects of this invention.

What is claimed is:

l. A cationic thermosetting resin composition comprising a mixture of a first polyamine polyamide polymer A, and for each mol of polymer A, from about 0.5 to about 14.4 mols of a second polyamine polyamide polymer B or C or a mixture thereof, said polymer A having been prepared by heating at a temperature of from about to about C. a mixture of:

a. a heterocyclic dicarboxylic acid of the formula:

HOOC-R- /c CH CH COOH where R is an alkylene radical containing from 1 to 10 carbon atoms or an arylene radical, and R is an alkylene radical containing from 3 to 10 carbon atoms;

c. a portion of the total amount of an amine which is a diamine of the formula H N-R"NH or a polyalkylenepolyamine of the formula H- N-(R NH- ),,H where R and R are alkylene groups containing from 2 to 6 carbon atoms, and n is an integer from 1 to 5; cooling the resulting first intermediate reaction product V111, combining d. itaconic acid with said first intermediate reaction product in an amount so as to provide an excess of itaconic acid with respect to carbonyl groups to 2i amine groups of said first intermediate and heating the mixture to a temperature of from about 1 10 to about 140C. under reflux to obtain a secondintermediate reaction product X, adding a further quan tity of reactant (c) to said second intermediate reaction product and effecting condensation and removal of water by heating the mixture to a temperature of about 185C, to form a water-soluble polyamide polyamine polymer X1, the proportions of reactants employed being from to 4 mols of reactant (b), 1 to 3 mols of reactant (c) and 1 to 2 mols of reactant (d) for each mol of reactant (a),

said polymer B having been prepared by heating together at reflux at about 105C a mixture of from 1 to mols of reactant (b) and from 1 to 4 mols of (c) to obtain intermediate polymer X111, cooling said reaction mixture and adding thereto incrementally from 1 to 3 mols of epichlorohydrin to form intermediate XIV, heating the reaction product to a temperature of from 160 to 185C. to obtain polymer XV; 1

said polymer C having been prepared by heating together at a temperature of from about 135 to about 165C. under reflux conditions a mixture of reactant (a), and for each mol of reactant (a), from 0 to 5 mols of reactant (b) and from 1 to 3 mols of reactant (c), adding water to said reaction mixture and cooling said mixture. to a temperature of from about 80 to about 90C., adding slowly to said reaction mixture from 1 to 3 mols of epichlorohydrin and heating the resulting mixture to a temperature from about 165 to about 215C. to remove water ofcondensation to obtain a polymer containing the repeating units XVII and XVlll adding to said mixture of polymers from about 0.5 to about 1.8 mols of epichlorohydrin per secondary amine group in said polymers and heating the resulting mixture at a temperature of from about 70 to about 76C. until a Gardner-Holdt viscosity.

greater than J is obtained.-

2. A cationic thermosetting resin composition according to claim 1 comprising a mixture of polymers A and B in the molar ratio of about 1.7 to '1.

3. Acationic thermosetting resin composition according to claim 2 in which 1 mol of reactant (b), 3 mols of reactant (c) and two mols of reactant (d) for each mol of reactant (a) are used in preparing polymer 5 A, and one mol of each of reactants (b), (c) and (e) are used in preparing polymer B, and sufficient epichlorohydrin is reacted with said polymers to convert all of the secondary amino groups thereof to tertiary amino groups.

4. A cationic thermosetting resin composition according to claim 1 comprising a mixture of polymers A andC in the molar ratio of 1:1.

5. A cationic thermosetting resin according to claim 4 in which 1 mol of reactant (b), 3 mols of reactant (c) and two mols of reactant (d) for each mol of reactant (a) are used in preparing polymer A: and 1 mol of reactant (b), 2 mols of reactant (c) and 1 mol of reactant (e) for each mol of reactant (a) are used in preparing polymer C, and sufficient additional epichlorohydrin is reacted with said polymers to convert all of the secondary amino groups thereof to tertiary amino groups.

6. A cationic thermosetting resin composition according to claim 5 wherein in forming each of said polymers A and C, reactant (a) is l-carboxypentyl- 4-carboxypyrrolidone formed by reacting itaconic acid with caprolactam; reactant (b) is caprolactam, and reactant (c) is diethylene triamine.

7. An improved wet strength paper comprising a web of paper-making fibers and from about 0.15% to 3.0%, 30 based on the weight of dry fibers, of the thermosetting resin composition of claim 1.

8. An improved wct strength paper comprising a web of paper-making fibersand from about 0.15% to 3.0%. based on weight of dry fibers, of the thermosetting resin 35 composition of claim 2.

9. An improved wet strength paper comprising a web of paper-making fibers and from about 0.15% to about 3.0%, based on weight of dry fibers, of the thermosetting resin composition of claim 4.

10. An improved wet strength paper comprising a web of paper-making fibers and from about 0.15% to about 3.0%, based on weight of dry fibers, of the ther' mosetting resin composition of claim 6.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, 9,3 2 Dated March 1975 Inventor(S) Francis S. Munj at and Samuel Ho Kim It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In the Specification Column 2, delete lines 34-38 inclusive Signed and Scaled this A ttes r:

RUTH C. MASON C. MARSHALL DANN Alrcsll'ng ()jfz'rer (ummissirmvr nflau'nls and Trademarks ORM PO-1050 (IO-69) USCOMM-DC 60376-P69 w as GOVERNMENT PRINTING OFFICE: 1969 o-3s6-s34. 

1. A CATIONIC THERMOSETTING RESIN COMPOSITION COMPRISING A MIXTURE OF A FIRST POLYAMINE POLYAMIDE POLYMER A, AND FOR EACH MOL OF POLYMER A, FROM ABOUT 0.5 TO ABOUT 14.4 MOLS OF A SECOND POLYAMINE POLYAMIDE POLYMER B OR C OR A MIXTURE THEREOF, SAID POLYMER A HAVING BEEN PREPARED BY HEATING AT A TEMPERATURE OF FROM ABOUT 150* TO ABOUT 165*C. A MIXTURE OF: A. A HETEROCYCLIC DICARBOXYLIC ACID OF THE FORMULA:
 2. A cationic thermosetting resin composition according to claim 1 comprising a mixture of polymers A and B in the molar ratio of about 1.7 to
 1. 3. A cationic thermosetting resin composition according to claim 2 in which 1 mol of reactant (b), 3 mols of reactant (c) and two mols of reactant (d) for each mol of reactant (a) are used in preparing polymer A, and one mol of each of reactants (b), (c) and (e) are used in preparing polymer B, and sufficient epichlorohydrin is reacted with said polymers to convert all of the secondary amino groups thereof to tertiary amino groups.
 4. A cationic thermosetting resin composition according to claim 1 comprising a mixture of polymers A and C in the molar ratio of 1:1.
 5. A cationic thermosetting resin according to claim 4 in which 1 mol of reactant (b), 3 mols of reactant (c) and two mols of reactant (d) for each mol of reactant (a) are used in preparing polymer A; and 1 mol of reactant (b), 2 mols of reactant (c) and 1 mol of reactant (e) for each mol of reactant (a) are used in preparing polymer C, and sufficient additional epichlorohydrin is reacted with said polymers to convert all of the secondary amino groups thereof to tertiary amino groups.
 6. A cationic thermosetting resin composition according to claim 5 wherein in forming each of said polymers A and C, reactant (a) is 1-carboxypentyl- 4-carboxypyrrolidone formed by reacting itaconic acid with caprolactam; reactant (b) is caprolactam, and reactant (c) is diethylene triamine.
 7. An improved wet strength paper comprising a web of paper-making fibers and from about 0.15% to 3.0%, based on the wEight of dry fibers, of the thermosetting resin composition of claim
 1. 8. An improved wet strength paper comprising a web of paper-making fibers and from about 0.15% to 3.0%, based on weight of dry fibers, of the thermosetting resin composition of claim
 2. 9. An improved wet strength paper comprising a web of paper-making fibers and from about 0.15% to about 3.0%, based on weight of dry fibers, of the thermosetting resin composition of claim
 4. 10. An improved wet strength paper comprising a web of paper-making fibers and from about 0.15% to about 3.0%, based on weight of dry fibers, of the thermosetting resin composition of claim
 6. 